This entry includes the catalytic domain of HGSNAT (Heparan-alpha-glucosaminide N-acetyltransferase). It contains the conserved histidine in the active site (His269), thought to hold the acetyl group during the transfer across the membrane and required for its enzymatic activity. HGSNAT transfers an acetyl group from cytoplasmically derived acetyl-CoA to terminal N-glucosamine residues of heparan sulfate within the lysosomes [1].

1: Analysis of the biogenesis of heparan sulfate acetyl-CoA:alpha-glucosaminide N-acetyltransferase provides insights into the mechanism underlying its complete deficiency in mucopolysaccharidosis IIIC. Durand S, Feldhammer M, Bonneil E, Thibault P, Pshezhetsky AV; J Biol Chem. 2010;285:31233-31242. PMID:20650889